scholarly journals Optimal Loading Conditions for Controlled Movement of Anterior Teeth in Sliding Mechanics

2009 ◽  
Vol 79 (6) ◽  
pp. 1102-1107 ◽  
Author(s):  
Jun-ya Tominaga ◽  
Motohiro Tanaka ◽  
Yoshiyuki Koga ◽  
Carmen Gonzales ◽  
Masaru Kobayashi ◽  
...  
Keyword(s):  
Tooth Movement ◽  
Anterior Segment ◽  
Orthodontic Tooth Movement ◽  
Loading Conditions ◽  
Maxillary Central Incisor ◽  
Bodily Movement ◽  
Anterior Teeth ◽  
Optimal Loading ◽  
Sliding Mechanics ◽  
Retraction Force

Abstract Objective: To determine optimal loading conditions such as height of retraction force on the power arm and its position on the archwire in sliding mechanics. Materials and Methods: A 3D finite element method (FEM) was used to simulate en masse anterior teeth retraction in sliding mechanics. The degree of labiolingual tipping of the maxillary central incisor was calculated when the retraction force was applied to different heights of a power arm set mesial or distal to the canine. Results: When the power arm was placed mesial to the canine, at the level of 0 mm (bracket slot level), uncontrolled lingual crown tipping of the incisor was observed and the anterior segment of the archwire was deformed downward. At a power arm height of 5.5 mm, bodily movement was produced and the archwire was less deformed. When the power arm height exceeded 5.5 mm, the anterior segment of the archwire was raised upward and lingual root tipping occurred. When the power arm was placed distal to the canine, lingual crown tipping was observed up to a level of 11.2 mm. Conclusions: Placement of the power arm of an archwire between the lateral incisor and canine enables orthodontists to maintain better control of the anterior teeth in sliding mechanics. Both the biomechanical principles associated with the tooth's center of resistance and the deformation of the archwire should be taken into consideration for predicting and planning orthodontic tooth movement.

scholarly journals Determining the Center of Resistance of Maxillary Anterior Teeth Subjected to Retraction Forces in Sliding Mechanics

2007 ◽  
Vol 77 (6) ◽  
pp. 999-1003 ◽  
Author(s):  
Sheau Soon Sia ◽  
Yoshiyuki Koga ◽  
Noriaki Yoshida
Keyword(s):  
Tooth Movement ◽  
Anterior Tooth ◽  
Central Incisor ◽  
Clinical Factor ◽  
Maxillary Central Incisor ◽  
Anterior Teeth ◽  
Sliding Mechanics ◽  
Retraction Force ◽  
Center Of Resistance

Abstract Objective: To determine the location of center of resistance and the relationship between height of retraction force on power arm (power-arm length) and movement of anterior teeth (degree of rotation) during sliding mechanics retraction. Materials and Methods: Three human subjects with maxillary protrusion were selected for this study. Initial tooth displacements of maxillary right central incisor under sliding mechanics with various heights of retraction forces were measured in vivo using a two-point three-dimensional displacement magnetic sensor device. By calculating the angle of rotation from the displacements measured, the location of the center of resistance was determined. Results: The results suggested that different heights of retraction forces could affect the direction of anterior tooth movement. The higher the retraction force was applied, the lower the degree of rotation (crown-lingual tipping) would be. The tooth rotation was in the opposite direction (from crown-lingual to crown-labial) if the height of the force was raised above the level of the center of resistance. Conclusion: The location of the center of resistance of the maxillary central incisor was approximately 0.77 of the root length from the apex. During anterior tooth retraction with sliding mechanics, controlled crown-lingual tipping, bodily translation movement, and controlled crown-labial movement could be achieved by attaching a power-arm length that was lower, equivalent, or higher than the level of the center of resistance, respectively. The power-arm length could be the most easily modifiable clinical factor in determining the direction of anterior tooth movement during retraction with sliding mechanics.

Optimal loading conditions for controlled movement of anterior teeth in sliding mechanics

2010 ◽  
Vol 69 (4) ◽  
pp. 129-130
Author(s):  
Jun-ya Tominaga ◽  
Motohiro Tanaka ◽  
Yoshiyuki Koga ◽  
Carmen Gonzales ◽  
Masaru Kobayashi ◽  
...  
Keyword(s):  
Loading Conditions ◽  
Anterior Teeth ◽  
Optimal Loading ◽  
Sliding Mechanics

scholarly journals Dual-section versus conventional archwire for en-masse retraction of anterior teeth with direct skeletal anchorage: a finite element analysis

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Ryo Hamanaka ◽  
Daniele Cantarella ◽  
Luca Lombardo ◽  
Lorena Karanxha ◽  
Massimo Del Fabbro ◽  
...  
Keyword(s):  
Finite Element ◽  
Tooth Movement ◽  
Occlusal Plane ◽  
Skeletal Anchorage ◽  
Element Analysis ◽  
Posterior Teeth ◽  
Posterior Portion ◽  
Anterior Teeth ◽  
Retraction Force ◽  
En Masse Retraction

Abstract Background The aim of this study is to compare the biomechanical effects of the conventional 0.019 × 0.025-in stainless steel archwire with the dual-section archwire when en-masse retraction is performed with sliding mechanics and skeletal anchorage. Methods Models of maxillary dentition equipped with the 0.019 × 0.025-in archwire and the dual-section archwire, whose anterior portion is 0.021 × 0.025-in and posterior portion is 0.018 × 0.025-in were constructed. Then, long-term tooth movement during en-masse retraction was simulated using the finite element method. Power arms of 8, 10, 12 and 14 mm length were employed to control anterior torque, and retraction forces of 2 N were applied with a direct skeletal anchorage. Results For achieving bodily movement of the incisors, power arms longer than 14 mm were required for the 0.019 × 0.025-in archwire, while between 8 and 10 mm for the dual-section archwire. The longer the power arms, the greater the counter-clockwise rotation of the occlusal plane was produced. Frictional resistance generated between the archwire and brackets and tubes on the posterior teeth was smaller than 5% of the retraction force of 2 N. Conclusions The use of dual-section archwire might bring some biomechanical advantages as it allows to apply retraction force at a considerable lower height, and with a reduced occlusal plane rotation, compared to the conventional archwire. Clinical studies are needed to confirm the present results.

scholarly journals Tooth Movement Efficacy of Retraction Spring Made of a New Low Elastic Modulus Material, Gum Metal, Evaluated by the Finite Element Method

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2934
Author(s):  
Naohiko Tamaya ◽  
Jun Kawamura ◽  
Yoshinobu Yanagi
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Tooth Movement ◽  
The Finite Element Method ◽  
Bodily Movement ◽  
Anterior Teeth ◽  
Low Elastic Modulus ◽  
Space Closure ◽  
Gum Metal ◽  
Element Method

The aim of this study was to evaluate the tooth movement efficacy of retraction springs made of a new β-titanium alloy, “gum metal”, which has a low Young’s modulus and nonlinear super elasticity. Using double loop springs incorporated into an archwire made of gum metal (GUM) and titanium molybdenum alloy (TMA), the maxillary anterior teeth were moved distally to close an extraction space. The long-term movements were simulated by the finite element method. Its procedure was constructed of two steps, with the first step being the calculation of the initial tooth movement produced by elastic deformation of the periodontal ligament, and in the second step, the alveolar socket was moved by the initial tooth movement. By repeating these steps, the tooth moved by accumulating the initial tooth movement. The number of repeating calculations was equivalent to an elapsed time. In the GUM and TMA springs, the anterior teeth firstly tipped lingually, and then became upright. As a result of these movements, the canine could move bodily. The amount of space closure in GUM spring was 1.5 times that in TMA spring. The initial tipping angle of the canine in the GUM spring was larger than that in the TMA spring. The number of repeating calculations required for the bodily movement in the GUM spring was about two times that in the TMA spring. It was predicted that the speed of space closure in the GUM spring was smaller than that in the TMA spring.

scholarly journals Finite Element Analysis of Mandibular Anterior Teeth with Healthy, but Reduced Periodontium

2021 ◽  
Vol 11 (9) ◽  
pp. 3824
Author(s):  
Ioana-Andreea Sioustis ◽  
Mihai Axinte ◽  
Marius Prelipceanu ◽  
Alexandra Martu ◽  
Diana-Cristala Kappenberg-Nitescu ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Periodontal Ligament ◽  
Tooth Movement ◽  
Orthodontic Tooth Movement ◽  
Real Data ◽  
Element Analysis ◽  
Anterior Teeth ◽  
Applied Forces ◽  
Orthodontic Forces

Finite element analysis studies have been of interest in the field of orthodontics and this is due to the ability to study the stress in the bone, periodontal ligament (PDL), teeth and the displacement in the bone by using this method. Our study aimed to present a method that determines the effect of applying orthodontic forces in bodily direction on a healthy and reduced periodontium and to demonstrate the utility of finite element analysis. Using the cone-beam computed tomography (CBCT) of a patient with a healthy and reduced periodontium, we modeled the geometric construction of the contour of the elements necessary for the study. Afterwards, we applied a force of 1 N and a force of 0.8 N in order to achieve bodily movement and to analyze the stress in the bone, in the periodontal ligament and the absolute displacement. The analysis of the applied forces showed that a minimal ligament thickness is correlated with the highest value of the maximum stress in the PDL and a decreased displacement. This confirms the results obtained in previous clinical practice, confirming the validity of the simulation. During orthodontic tooth movement, the morphology of the teeth and of the periodontium should be taken into account. The effect of orthodontic forces on a particular anatomy could be studied using FEA, a method that provides real data. This is necessary for proper treatment planning and its particularization depends on the patient’s particular situation.

scholarly journals Highly variable rate of orthodontic tooth movement measured by a novel 3D method correlates with gingival inflammation

2020 ◽  
Author(s):  
Marc A. de Gouyon Matignon de Pontouraude ◽  
Johannes W. Von den Hoff ◽  
Frank Baan ◽  
Robin Bruggink ◽  
Marjon Bloemen ◽  
...  
Keyword(s):  
Biological Markers ◽  
Orthodontic Treatment ◽  
Tooth Movement ◽  
Gingival Crevicular Fluid ◽  
Contact Point ◽  
Anterior Segment ◽  
Three Dimensional ◽  
Orthodontic Tooth Movement ◽  
Large Individual ◽  
Gingival Inflammation

Abstract Objectives Individual orthodontic treatment duration is hard to predict. Individual biological factors are amongst factors influencing individual rate of orthodontically induced tooth movement (OTM). The study aim is to determine the rate of OTM by a novel 3D method and investigate parameters that may predict the rate of tooth movement. Materials and methods In this prospective cohort study, rate of OTM was determined from 90 three-dimensional intra-oral scans in 15 patients (aged 12–15) undergoing orthodontic treatment. For each patient, intra-oral scans were taken every week for up to 6 weeks (T0–T5). The teeth were segmented from the scans and the scans were superimposed on the palatal rugae. The rate of OTM was calculated for each tooth. Other parameters were gingival inflammation, contact-point displacement and the biological markers, matrix metalloproteinases (MMP), MMP-9 and MMP-2 in gingival crevicular fluid (GCF). Results Our study showed a high variation in the rate of OTM, varying from 0.15 to 1.24 mm/week. Teeth in the anterior segment tended to move more compared with the posterior segment. The contact point displacement and gingival inflammation varied greatly amongst the patients. The MMPs measured did not correlate with tooth movement. However, the gingival inflammation index showed a significant correlation with OTM. Future studies should include other biological markers related to bone-remodeling. Conclusion This novel and efficient 3D method is suitable for measuring OTM and showed large individual variation in rate of OTM. Clinical relevance Patients show different rates of OTM. The rate of OTM in an individual patient can provide guidance in timing of follow-up appointments.

scholarly journals Effect of platelet-rich plasma on the rate of orthodontic tooth movement:

2020 ◽  
Vol 90 (3) ◽  
pp. 354-361 ◽  
Author(s):  
Ahmed El-Timamy ◽  
Fouad El Sharaby ◽  
Faten Eid ◽  
Amr El Dakroury ◽  
Yehya Mostafa ◽  
...  
Keyword(s):  
Tooth Movement ◽  
Platelet Rich Plasma ◽  
Orthodontic Tooth Movement ◽  
The Other ◽  
Positive Potential ◽  
Canine Retraction ◽  
Steady Rate ◽  
Significant Difference ◽  
To Receive ◽  
Retraction Force

ABSTRACT Objective To investigate the effect of local injection of platelet-rich plasma (PRP) on the rate of orthodontic tooth movement. Materials and Methods Sixteen female patients were randomly allocated in a split-mouth study design to receive PRP injections with CaCl2 activating solution on one side (intervention side) while the other side received CaCl2 injection only (control side). Canine retraction was performed on 0.017 × 0.025-inch stainless steel archwire applying 1.5 N retraction force. PRP and CaCl2 injections were done at 0, 3, and 6 weeks. The duration of the study was 4 months. Data were collected from digitized models. Assessment of pain accompanying the procedure was done using a visual analogue scale. Results The rate of canine retraction was faster on the intervention side in the first 2 months, with a statistically significant difference in the first month (P = .049). On the other hand, the rate was statistically significantly slower on the intervention side in the third month following cessation of PRP injections (P = .02). Pain increased following injections on both sides. Conclusions PRP showed a positive potential to accelerate the rate of tooth movement when injected in the first 2 months. Repeated injections of PRP to maintain a steady rate of accelerated tooth movement warrant further investigation.

scholarly journals Quantification of intrusive/retraction force and moment generated during en-masse retraction of maxillary anterior teeth using mini-implants: A conceptual approach

2017 ◽  
Vol 22 (5) ◽  
pp. 47-55 ◽  
Author(s):  
A. Sumathi Felicita
Keyword(s):  
Clinical Outcomes ◽  
Anterior Segment ◽  
Applied Force ◽  
Occlusal Plane ◽  
Conceptual Approach ◽  
Mini Implants ◽  
Anterior Teeth ◽  
Clinical Scenarios ◽  
Retraction Force ◽  
En Masse Retraction

ABSTRACT Objective: The aim of the present study was to clarify the biomechanics of en-masse retraction of the upper anterior teeth and attempt to quantify the different forces and moments generated using mini-implants and to calculate the amount of applied force optimal for en-masse intrusion and retraction using mini-implants. Methods: The optimum force required for en-masse intrusion and retraction can be calculated by using simple mathematical formulae. Depending on the position of the mini-implant and the relationship of the attachment to the center of resistance of the anterior segment, different clinical outcomes are encountered. Using certain mathematical formulae, accurate measurements of the magnitude of force and moment generated on the teeth can be calculated for each clinical outcome. Results: Optimum force for en-masse intrusion and retraction of maxillary anterior teeth is 212 grams per side. Force applied at an angle of 5o to 16o from the occlusal plane produce intrusive and retraction force components that are within the physiologic limit. Conclusion: Different clinical outcomes are encountered depending on the position of the mini-implant and the length of the attachment. It is possible to calculate the forces and moments generated for any given magnitude of applied force. The orthodontist can apply the basic biomechanical principles mentioned in this study to calculate the forces and moments for different hypothetical clinical scenarios.

scholarly journals Finite element study of controlling factors of anterior intrusion and torque during Temporary Skeletal Anchorage Device (TSAD) dependent en masse retraction without posterior appliances: Biocreative hybrid retractor (CH-retractor)

2019 ◽  
Vol 90 (2) ◽  
pp. 255-262 ◽  
Author(s):  
Sung-Seo Mo ◽  
Min-Ki Noh ◽  
Seong-Hun Kim ◽  
Kyu-Rhim Chung ◽  
Gerald Nelson
Keyword(s):  
Finite Element ◽  
Anterior Segment ◽  
Two Dimensions ◽  
Element Analysis ◽  
Bodily Movement ◽  
Anterior Teeth ◽  
Temporary Skeletal Anchorage ◽  
Anterior Segments ◽  
Sophisticated Analysis ◽  
En Masse Retraction

ABSTRACT Objectives: To evaluate, using the finite element method (FEM), the factors that allow control of the anterior teeth during en masse retraction with the Biocreative hybrid retractor (CH-retractor) using different sizes of nickel-titanium (NiTi) archwires and various gable bends on the stainless-steel (SS) archwires. Materials and Methods: Using FEM, the anterior archwire section, engaged on the anterior dentition, was modeled in NiTi, and another assembly, the posterior guiding archwire, was modeled in SS. Two dimensions (0.016 × 0.022- and 0.017 × 0.025-inch NiTi) of the anterior archwires and different degrees (0°, 15°, 30°, 45°, and 60°) of the gable bends on the guiding wire were applied to the CH-retractor on the anterior segment to evaluate torque and intrusion with 100-g retraction force to TSADs. Finite element analysis permitted sophisticated analysis of anterior tooth displacement. Results: With a 0° gable bend all anterior teeth experienced extrusion. The canines showed a larger amount of extrusion than did the central and lateral incisors. With a gable bend of >15°, all anterior teeth exhibited intrusion. Bodily movement of the central incisor required a 30°∼45° gable bend when using anterior segments of 0.016 × 0.022-inch NiTi and 15°∼30° gable bend with the 0.017 × 0.025-inch NiTi. Conclusions: With the CH-retractor, varying the size of the NiTi archwire and/or varying the amount of gable bend on the SS archwire affects control of the anterior teeth during en masse retraction without a posterior appliance.

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